1. Field of the Invention
The present invention relates to spiro-pyrazoline derivatives having a novel skeleton and to a method for producing these spiro-pyrazoline derivatives having a novel skeleton.
More specifically, the invention is concerned with derivatives of spiro-pyrazoline, such as spiro(indoline-2,5'-pyrazoline), spiro(dihydroquinoline-2,5'-pyrazoline), spiro(dihydroquinoline-4,5'-pyrazoline), etc., and a method for their production comprising reacting a 2-methyleneindoline derivative, a 2-methylenedihydroquinoline derivative, 4-methylenedihydroquinoline derivative or a precursor thereof, such as a 2-methylindolenium salt derivative, a 2-methylquinolinium salt derivative, and 4-methylquinolinium salt derivative and benzphenylhydrazide chloride derivative in a solvent in the presence of an excessive amount of a base.
2. Description of the Prior Art
It is known that a hydrazide chloride gives an active intermediate product "nitrile imine" in the presence of a tertiary amine and a 1,3-dipole cycloaddition reaction with various multi-bonds takes place with this active material, as described, e.g., R. Huisgen, Angewandte Chemie, 75, 604(1963). However, it has never been reported that a spiro bond, as is obtained in this invention described hereinafter, is formed by the reaction of such a "nitrile imine" and an exo-methylene compound. Also, as the result of detailed research it has been confirmed that every exo-methylene compound does not always react under the conditions of the production method of this invention. Accordingly, it has become clear that only certain exo-methylene compounds can form spiro bonds similar to those in this invention. For instance, it is reported that when the active "nitrile imine" is allowed to stand in an inert solvent, a dimerized dihydrotetrazine is obtained. However, when the nitrile imine is reacted in the presence of 3-ethyl-2-methylenebenzthiazoline under the reaction conditions of this invention, no addition compound (1 : 1) having a spiro bond is obtained and only a dimer is isolated.
An object of the present invention is to provide spiro-pyrazoline derivatives having a novel structure, which can be used as organic photoconductive materials for electrophotography, organic fluorescent materials, and additives for silver salt and non-silver salt photographic materials and methods for preparing these derivatives.